Might I add another suggestion? I guess this all hinges on several things, like whether you are devoting the day for your husband & father in law to do this, and whether or not you are going to have a car at your disposal, but about 45 minutes up Interstate 4, there is a little place called Daytona, and they have a speedway up there as well. Maybe y'all have heard of it? Anyway, the Richard Petty crew also does the same stuff up there as at the WDW Speedway, and it is the most incredible experience for anyone who lives vicariously through their favorite NASCAR driver. I've done it before, and there is no comparison to driving close to 160 miles per hour on the famed high banks at Daytona. When I was done, I felt like I was following in the footsteps of Richard Petty himself. I doubt that King Richard ever drove a car at Walt Disney World.
The Richard Petty Driving Experience has a website that describes everything that goes on at the speedways. If this sounds like something feasible, I highly suggest checking it out.